Piano conditioner



NW' 21 1957 1.5. HABIG ETAL l PIANO CONDITIONER 5 sheets-sheet 2 Filed Oct. 16, 1963 N, -Qa

` INVENTORS JOHN a. HABIG MAURICE E.scHuLER ATTORNEYS UN'ov; 21, 1967 J. B. HABIG ETAL .PIANO CONDITONER Filed dat. 16, 1963 5 Sheets-Sheet 5 MIQE INVENTORS JOHN B. HABIG E E. SCHULER Th, l' 'f e ATTORNEYS United States Patent iitiee 3,353,434 PIANO CONDETINER John B., Habig, Jasper, and Maurice E. Schuler, Evansville, Ind., assignors to W. W. Kimball Co., Jasper, Ind., a corporation of Delaware Filed st. 15, 1963, Ser.. No. 316,75) 8 Claims. (Cl. SLi-454) This invention relates to a method and apparatus for the stabilization of a newly manufactured key operated musical instrument and is more particularly concerned with the stabilization of piano keys and piano key action.

It is a well known fact that the most important quality in a piano is the tone and it is also true that the true tone of the instrument does not fully develop until about nine months after the date of manufacture.

Some of the factors affecting the tone during this settling period are: the varnish on the sound board crystallizes, the pressure on the sound board through the bridge settles down, and the key action becomes stabilized.

Forming a part of goed tone are uniform tone color at various frequency ranges and volume levels, true pitch and a clean attack when the hammers in the piano strike the strings.

Since the tone of the piano is affected by the sharpness or crispness of key action, it has always been desired for settling of the key action of a piano to take place at a rapid pace. lf more uniform, stabilized key action could be produced economically at the factory, pianos of consistent quality of tone could more readily be produced. Heretofore, however, as far as is known to us, this has not been possible except by laborious manual manipulation of the keys.

Many of the pianos produced today have more than forty (40) parts involved in the linkage between the key which is struck with a finger and the hammer which strikes the string. Obviously, with that many parts in so short a distance, trouble may develop. With the applicants invention, the piano is mechanically given the equivalent of many hours of playing use while at the factory in order to stabilize the key action and to detect any tiaws which may be present before the instrument is shipped to a'customer.

Other factors which enhance the stability of the tuning of a piano and which are accomplished by the practice of the present invention include the setting of the strings at all the bearing points thereof, the vibrating elasticity in the new strings, and the detecting of faults in the wound strings in the base section of the strings. Furthermore, the tuning pins and hitch pins all become firmly seated by the practice'of this invention and these several factors contribute materially to the presenting to the purchaser of a piano in optimum playing condition, and with optimum stability as to tuning and key action and the like.

Prior methods for testing the key action include the laborious manual method; however applicants know of no mechanical stabilizer prior to the present invention.

With a stabilized key action, the weight of touch (usually about two ounces) of the individual keys can be more readily set to insure uniform weight of touch which ultimately affects the tone of the piano.

With the foregoing in mind, an object of applicants invention is to provide an economical, mechanical apparatus for settling or stabilizing the key action of a piano.

A further object is to provide an apparatus which can be readily moved from one piano to another and readily adjusted to conform to a standard piano keyboard of eighty-eight (88) keys or keyboards having more or less keys.

A still further object is to provide an apparatus for 3,353,434 Patented Nov. 2l, 1967 stabilizing the key action which can operate at varying speeds and at an economical cost.

These and other objects and advantages of this invention will become more apparent upon reference to the following specification taken in connection with the accompanying drawings, in which:

FIGURE l is a side View of a piano action stabilizer according to the present invention showing the driving and adjusting means;

FlGURE 2 is a front view of the stabilizer;

FIGURE 3 is a top view of the stabilizer showing the key actuators and the drive shaft for the actuators;

FlGURE 4 is an enlarged perspective view of two key actuators and the actuator drive shaft; and

FIGURE 5 is a cross sectional view of a key actuator taken along lines 4-4 of FIGURE 4.

General arrangement This invention relates to a portable piano key and key action stabilizer which can be rolled into position at the piano and which can be readily adjusted to conform to the specific piano being stabilized.

The piano stabilizer generally consists of a framework which is adjustable in height and which is mounted on a movable platform.

In the device, a series of resilient hammer means which strike the piano keys are connected to individual levers which are pivotally mounted in the framework.

The individual levers are actuated by a series of lobes which are arranged in a helical pattern on a rotating cylinder which is driven by a motor through a variable speed gear reduction unit.

There are adjusting means on the framework itself and on the individual hammers to accurately position one hammer over each black and white key on the piano keyboard.

As the cylinder is driven, the lobes thereon raise one end of the levers causing the hammers at the other end of the lever to strike the respective key. As the cylinder continues to rotate in a clockwise direction, the lobes are disengaged from the end of the levers causing the end associated therewith to fall thereby raising the hammers from the keys.

As the cylinder continues to rotate, the above action is repeated for each key which stabilizes the keys and brings about the advantages previously mentioned.

Structural arrangement Referring to the drawings more in detail, FGURE 1 shows the side view of the stabilizer generally designated at 10 as it is in position over the piano 12 being stabilized.

The invention is mounted on a base member 14 which is supported on casters 16. Two vertical supporting hollow columns 18 are welded to the base 14 as shown.

To provide for vertical adjustment of the stabilizer 1t), there is an outer tube 20 which is in telescoping engagement with each stationary column 18. There is a nut 22 welded in the top of each column 18 which receives the adjusting screw 24 which is associated with each outer tube 20.

The screw 24 is inserted through an opening in the upper closed end 26 of tube 20 and freely rotates therein while it is fixed against axial movement in tube 20 by the bushing 28 and pin 30 on the underside of end 26 by locking collar 32 on top of end 26. A removable crank 34 having a central hub 36 with a slot 38 therein, and a pin 40 retained in screw 24 provides the means to advance or withdraw screws 24 in nuts 22 thereby respectively lowering or raising the stabilizer 10.

Reinforcing horizontal plate 42 is welded to outer tubes 20 as shown and provides rigidity to the frame.

A- drive motor 43 is mounted on platform 42 which rests on an inverted C beam 44 which is spaced therefrom by bushing 46. Bolty means 48 anchor beam 44 to nuts 46 which are welded to collars 47 on tubes 20. Oifon switch 50 is provided to control the supply of electricity to motor 43.

Also part of the framework ofy the structure are side" plates 52 which'are welded to tubular supports 54, which, in turn, are weldedto collars 56`o-n tubes 20. Bolt 53J engages threads in collars 56 to lock the collars in position on tubes 20. Angle support member 6:0'. extends between side plates 52 and is welded thereto as' shown in FIGURES 1 and2.

The front end of side plates 52 have threadedlsleeves 62 which arewelded' to forward section 64. Adjusting screws 66, eachv with adjusting knob 68 on one end' and shoe 70'with padding swivelly mounted on the lower end provide an adjustingfmeans to position the apparatus over the keyboard surface of the piano, indicatedrat 72. A`s` seen in FIGURES, the forward section 64- of the side plates Vare bent outwardly at 74 to bring thescrew 66 over a supportable area 72 on the piano case.

FIGURE 3 shows the method of mounting of actuator cam carrier 76. This carrier supports andl `drives the individual key actuators on the keyboard ofthe piano as will be discussed in detail hereinafter.

The carrier 76 has a shaft 78 extending out through holes in side plates 52 Aand'througll ange mounted bearings 80 which are secured to side plates 52 by bolts 82. The carrier 76 rotates in the bearings 80 and is driven by pulley 84 on one end of shaft 78.

Drive belt 86 connects pulley 84 with driving pulley 8,8 and-both pulleys and belt are covered by a protective shield 90.

Pulley 88 is driven by shaft 92 from a standard variable speed transmission 94 which is connected with motor 43. Control knob 96 varies theV output speed of the transmission to obtain variable speeds of revolution per minute of shaft 78of carrier 76.

Drive shaft 92 is supported on the far end byfbearing means 98 of known variety which is anchored-to the inverted C beam 44.-

As shown in FIGURES 3 and-4, there are a series of cam lobes 100 arranged-on the periphery of the` carrier 76 to forma helical pattern thereon. There is one lobev 100 for eachfkey actuator lever generally designated'102 and each black and white key on the piano bcingtstabilized is struckonce during each revolution'ofshaft 76.v

The keyy actuator levers 102- with bearings 104 a-re'r pivotally mounted on a shaft 106 which is` anchoredin side plates 52.

The levers 102 are shown in FIGURE 4 and consist of a' bar108' with a weight 110 attached on one end, and

with the resilient actuator plungers'generally designatedl 112 on the other end. Asseen the actuator levers 102 may be pivotally mounted in the weighted section 110. The

actuators striking the white keys 114have a lever/bar 116 which is shorter than lever 108which' reaches black keys 118, but-in'all other respects,-lever bars 11641 are the same.l Spacers 119lmounted. on' shaft 1041' establish the spaced parallel relationship -of the levers;

As the` carrier turns' in a' clockwise direction, the

appropriate cam lobe 100 engages the end of the pertainV-` ingllever-as at 120 causing-the` actuator lever 102 to pivot with key actuator plungers 112 depressing the appropriate piano key. VThe carrier 76`co'ntinues in a clockwise direction until it disengages pertainingcam 100 from-the end 120 causing weight 110 `to`v return lever116 to resting position.

In therestingposition, the weighted section 110 rests upon a resilient stop 122- which is mounted on stop 124 which is. Welded to angleisupport 60 as shown inrFIG- URE4.

FIGURE shows the construction Vof the key actuator 112.1 The actuatorconsists of a-bolt 126 which freely slides bolt 126, and-the adjustment isfixedfby spring 134 which keeps the nut inplace'.- The spring 134 also' provides some resilience when depressing the keysl asl the levers 102 are cammed-by lobes`100.'

Operation of the apparatus In operating the piano stabilizer 10,.the stabilizer is moved into position over the piano keyboard. The verticalcolumns 20 can be adjusted to theV proper heightyif necessary, by turning crank 34.

When positioned over the keyboard, the Kclamp means on the forward end of the apparatus can -be adjusted-to bring shoe 70 in contact with the piano at 72 thereby locking the stabilizer 10 in place so that one actuator 112v is over each key on the keyboard.

The individual actuators 112 are then adjusted via nuts 132, if necessary, to provide the appropriate clearance over the keys. Y

The motor 43 is then energized to drive carrier 76. As the carrier turns, the cams thereon depress each actuator lever 102 once for each revolution of the carrier as previously explained.

The time required for stabilizing the piano keys will be dependent upon the speed of the carrier 76 and the specific needs of the piano, but generally a shaft speedof 40' r.p.m. for a length of 10 minutes will suffice.

The depressing of the keys by the device according to the present invention is such that manual playing is substantially duplicated and uniformly from one end of the keyboard -to the other so that the complete piano actionand all of the strings, bearings and supports therefore are uniformly worn in into a stable condition,.andany faults in the action of any of the strings, particularlythe wound strings, can be detected before the piano leaves the factory and any faults of this nature corrected.

While this invention deals with a Ipiano ofstantlard size, it'is understood'that this invention could be modified" to perform the same functions on other instruments, such as organs andaccordions.

Itwill be understood that this invention is su'sceptit'alex tical supporting columns in spaced relation thereon, mov-V able columns in telescoping enga-gement with said supporting `columns and having height` adjusting means associated therewith, side plate means connected with eachY said movable column, and having forward portions `adapted for positioning over said keyboard, horizontal reinforcing means connecting said side plates, horizontal reinforcingy means connecting said movable columns-clamping means mounted on said forwardvportions forholding1 said Side plate means in fixed relation to said keyboard, resilient activator means pivotallyv mounted between saidside plate means and adapted for positioning over and engaging and depressing each key on said keyboard, activating means rotatably mounted betweensaidlside'plate meansU for repetitively engaging each said activator rneans,`.an`d' variable'speeddriving means mounted on said framean'd drivingly connected to said activating means;

2. The apparatus. as -claimedfin claim 1in which saidv resilient activator means comprises; a'shaftextendirlg be- WQeQ and .1.1.13 ?1 1.Qreflv to said side plates, a pluralityof' levers having a forward end and a rearward Weighted end pivotally mounted on said shaft in spaced parallel -relationship, a key activator connected to the forward end of each said lever and adaptable for engaging a key on said keyboard, each said key activator comprising a sleeve kvertically aligned and fixed to the forward end of each said lever, a bolt slidably mounted in said sleeve, a nut having a resilient pad on the reverse side thereof, said nut in threaded engagement with said bolt and a spring mounted around said bolt between said nut and said sleeve, and resilient stop means mounted on said horizontal reinforcing means yconnecting said slide plates for each said lever.

3. The apparatus as claimed in claim 2 in which said activating means comprises; an activator shaft rotatably mounted in said side plates for rotation in a clockwise direction, a plurality of caming lobes one for each said lever spaced on said activator shaft to form a helix on the surface thereof, each said caming lobe activating the lever associated therewith once during each revolution of said activator shaft to cause said key activator to strike said keys.

`4. An apparatus for stabilizing the keys and key action of a piano keyboard comprising; a frame comprising a movable platform having two vertical supporting columns anchored in spaced relation thereon, movable columns in telescoping engagement with said supporting columns and having height adjusting means associated therewith lfor adjusting said frame to said keyboard, a side plate means connected with each said movable column and having forward portions adaptable for positioning over said keyboard, horizontal reinforcing means extending -between and connecting said side plates, horizontal reinforcing means extending between and connected to said movable columns, clamping means mounted on said forward portions for holding said side plate means in fixed relation to said keyboard, a plurality of key activator means pivotally mounted in spaced parallel relationship between said side plate means and adaptable to be positioned over each key of said keyboard, each said key activator means comprising a lever pivotally mounted between said side plate means and having a forward end and a weighted rearward end, resilient hammer means mounted on said forward end adaptable for positioning over and striking a key on said keyboard, activating means for repetitively engaging said rearward ends to cause said hammers to strike said keys, abutment means mounted on said horizontal reinforcing means extending between said side plates upon which said rearward ends rest when in disengagement With said activating means, and variable speed driving means connected with said activating means to drive said key activator means1 5. An apparatus for stabilizing the keys and key action of a keyboard musical instrument having a keyboard comprising; a frame adapted for alignment and retention in a predetermined position relative to the keyboard of the musical instrument, a plurality of activator means mounted in said frame above said keys and each operable when actuated for engaging and depressing a respective key of said keyboard in a manner simulating normal actuation of the keys during playing of the instrument, actuator means in the frame operatively associated with said activator means operable when driven to actuate said activator means repetitively and in sequence, and drive means in said frame connected to said actuator means and energizable for driving said actuator means.

6. The combination according to claim 5 in which there is an activator means for each key of the keyboard so that driving of said actuator means will cause every key of the keyboard to be depressed.

7. The combination according to claim 6 in which said drive means is variable in speed.

8. An apparatus for stabilizing the key action of a musical instrument having a keyboard comprising; a vertically adjustable portable frame adapted for positioning and retention in a predetermined position relative to the instrument keyboard, a plurality of resilient activators pivotally mounted in said frame and each having one end positioned over a respective key on said keyboard when said frame is in said predetermined position, each activator being tiltable on its pivotal support for engaging and depressing its respective said key, activating means in said frame comprising a rotatable shaft having a lobe thereon for each activator, said lobes being adapted upon rotation of said shaft to engage the other ends of said activators and tilt the activators to cause the activators to depress their respective keys, said lobes being distributed circumferentially on said shaft to bring about depressing of said keys in a predetermined sequence, and drive means in the frame connected to said shaft and energizable for driving said shaft in rotation.

References Cited UNITED STATES PATENTS 1,051,156 1/1913 Olson 84 454 FOREIGN PATENTS 755,319 8/1956 Great Britain.

RICHARD B. WILKINSON, Primary Examiner, C: M; QVEIBEY, maar? Exminer. 

1. AN APPARATUS FOR STABILIZING THE KEYS ACTION OF A MUSICAL INSTRUMENT HAVING A KEYBOARD COMPRISING; A FRAME COMPRISING A MOVABLE PLATFORM HAVING TWO VERTICAL SUPPORTING COLUMNS IN SPACED RELATION THEREON, MOVABLE COLUMNS IN TELESCOPING ENGAGEMENT WITH SAID SUPPORTING COLUMNS AND HAVING HEIGHT ADJUSTING MEANS ASSOCIATED THEREWITH, SAID PLATE MEANS CONNECTED WITH EACH SAID MOVABLE COLUMN, AND HAVING FORWARD PORTIONS ADAPTED FOR POSITIONING OVER SAID KEYBOARD, HORIZONTAL REINFORCING MEANS CONNECTING SAID SIDE PLATES, HORIZONTAL REINFORCING MEANS CONNECTING SAID MOVABLE COLUMNS, CLAMPING MEANS MOUNTED ON SAID FORWARD PORTIONS FOR HOLDING SAID SIDE PLATE MEANS IN FIXED RELATION TO SAID KEYBOARD, RESILIENT ACTIVATOR MEANS PIVOTALLY MOUNTED BETWEEN SAID SIDE PLATE MEANS AND ADAPTED FOR POSITIONING OVER AND ENGAGING AND DEPRESSING EACH KEY ON SAID KEYBOARD, ACTIVATING MEANS ROTATABLY MOUNTED BETWEEN SAID SIDE PLATE MEANS FOR REPETITIVELY ENGAGING EACH SAID ACTIVATOR MEANS, AND VARIABLE SPEED DRIVING MEANS MOUNTED ON SAID FRAME AND DRIVINGLY CONNECTED TO SAID ACTIVATING MEANS. 